/Engine/Plugins/FX/Niagara/Source/NiagaraShader/Public/NiagaraShared.h
Checks to see if the shader map is already being compiled for another script, and if so adds the specified script to the list to be applied to once the compile finishes.
True if the shader map was being compiled and we added Script to the list to be applied.
bool TryToAddToExistingCompilationTask ( [FNiagaraShaderScript](API\Plugins\NiagaraShader\FNiagaraShaderScript) * Script )